


once you get it, you never want to quit

by myfavouritesweater



Category: It's Always Sunny in Philadelphia
Genre: First Time, M/M, Recreational Drug Use, they're both like 19/20, young and stupid and in love
Language: English
Status: Completed
Published: 2018-01-30
Updated: 2018-01-30
Packaged: 2019-03-11 07:49:22
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,414
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13519761
Author URL: https://archiveofourown.org/users/myfavouritesweater/pseuds/myfavouritesweater
Summary: Since Dennis came home last month, they’ve spent practically every day together. Mac hasn’t slept in his own bed for over a week.They lock eyes in the mirror, and Mac winks.---Or:The one where Mac and Dennis leave a party early to bang for the first time.





	once you get it, you never want to quit

Dennis hates parties. 

He hated them while he was at high school, and he hates them now he's at college. They’re full of assholes trying to get off, guys throwing themselves at anything with tits, girls giggling too much and bitching about each other. They’re exhausting, and never as great as people make them out to be.

But he’s back in Philly for the summer, and (for some ungodly reason) he’s agreed to go to one of Tim Murphy’s ragers.

Mac hates parties, too. They were made for each other in that way. 

So they’ve been in the bathroom for the past 20 minutes, avoiding their old school peers and snorting the shitty blow Mac stole from his Dad.

He watches Mac snort another line off the rim of the sink, eyelashes fluttering delicately as he straightens up. He rubs his nose, once, twice, and grins at Dennis. 

Dennis grins back. 

He's less graceful than Mac when it's his turn, having to go over the line twice, because his hands are shaking the whole time. He always shakes when he does coke, like his whole body is a live wire. 

It doesn't have anything to do with Mac hovering over his shoulder, hand low on his back. It doesn't. 

“Dude, I love this song,” Mac says excitedly. Dennis can barely hear the music coming from downstairs, too muffled by the heavy wooden door and the hoard of people outside and the blood rushing in his ears. 

“You wanna go dance?” He asks. He can feel the drug kicking in. It feels electric. 

“In a sec,” Mac nods, bumping Dennis out of the way with his hip to stand in front of the mirror. He starts fussing with his hair, as though it hasn’t looked the exact same for the past three years, and Dennis just watches. 

He misses Mac while he’s at college. Train fare is too expensive for him to come up more than once a month, and even then, he can’t always make it. 

Since Dennis came home last month, they’ve spent practically every day together. Mac hasn’t slept in his own bed for over a week.  

They lock eyes in the mirror, and Mac winks. 

Dennis likes coke. It gives him the confidence to look at Mac without holding back, to reach out and touch him if he wants to. When they’re drunk, or smoking weed, or whatever, he holds himself back until Mac gives in first, until he’s lost enough control to indulge himself. He’s still never kissed Mac sober. 

But he isn't sober. So when Dennis grips Mac’s shoulder and spins him round, Mac is already two steps ahead of him, pressing his warm mouth to Dennis’ before he's had chance to think. 

It's frantic, rushed, like time is running out. It's messy, all teeth and tongue, but goddammit if Dennis’ eyes aren't rolling into the back of his head. 

He moves his hands from Mac’s shoulders to grip at the back of his head, winding his fingers into the soft, ungelled hair at the nape of his neck. He likes it like this (has pictured his hands latching on to it before) and he uses it to pull him even closer. 

He doesn't even know how long they've been kissing, or if time is even still moving. He just knows that he can't get enough, and he doesn't know if he ever will. 

One of the warm hands clamped around his waist quickly leaves as Mac lifts it to cradle Dennis' cheek, fingers brushing the skin lightly, possessively. Dennis leans into the touch, a breathy moan slipping into Mac's mouth, and he lets his thighs fall open a little. 

One of Mac's quickly fills the empty space. 

When Mac's lips suddenly leave his own, he almost whines at the loss, until Mac's head falls to the side and he latches onto Dennis' neck, grinding his hips forward almost lazily. 

" _ God _ , Dennis," He breathes, sucking a mark just below Dennis' ear. Dennis lets his head fall back against the wall, moving his hips rhythmically with Mac's, and he thinks he could probably stay like this forever until-

"Some people have to piss!" A shrill voice screams from outside, followed by insistent pounding on the door.  

And then Mac's pulling away, eyes wild, lips puffy and wet, and he just stares at Dennis. His hair is messed up, sticking straight up at the back and lying flat at the front, and it's so obvious that they've been making out in here that Dennis wants to scream. 

“You want another line before we go back out?” Mac asks with a smile. Dennis feels the drag of Mac’s hard dick against his thigh as he steps back, and has to bite back a groan. 

“How ‘bout we wait ‘til we get back to mine?” Dennis says, raising an eyebrow. 

“But we’re not going back to yours for another - oh,” He says, realising, with a sly grin. “Yeah. Let’s do that.” 

He leans in and presses one last, long kiss into Dennis’ mouth, ignoring the shrieking girls outside, and Dennis’ heart jolts in his chest. He’s been planning for this. Tonight’s the night.

Dennis manages to will his dick back down to a semi, adjusting his pants so it's not too obvious, but Mac is forced to tuck his own into his waistband. Dennis runs a hand up its length teasingly as he goes to unlock the door. 

“You think you can wait until we get back to mine, big boy?” He says lowly, crowding right into his space. 

Mac is still gaping stupidly when Dennis swings the door open, strolling out and down the hall as though Mac was never in there with him. 

\--

They don't make it all the way home before Dennis has to pull Mac into a vacant Taco Bell parking lot, jerking him off quickly while adrenaline roars through his veins. Mac comes with a shout, biting down on Dennis’ bottom lip, and Dennis has to fight not to let himself go right there. 

He wants Mac to be the one to pull him undone, and he wants him to do it in a  _ bed _ . 

When they stumble in through Dennis’ front door, the living room light is on, meaning at least one member of his nightmarish family is still awake. He sends up a silent prayer hoping it's Dee and not his parents, hoping she doesn’t chat too long - or worse - follow them up to his room. 

Mac keeps kissing his neck, though, keeps trying to push him against the cool white wallpaper of the hallway, but Dennis shoves him off. He might be high as a fucking kite, might still be hard from just knowing Mac is next to him, but he’s still terrified of his family finding out about them.

“Why don't we just go straight upstairs?” Mac hisses, hooking his fingers through Dennis’ belt loops. Dennis indulges him for a moment, gives him a quick peck on the lips.

“If we say hi now, whoever’s still up is less likely to knock on my door later,” Dennis whispers back. 

He takes Mac’s hand and drags him into the front room, squinting in the light. It  _ is _ Dee sat up on the couch, thank god, yawning and watching TV. 

“Hey-o,” Mac says to her, voice too loud in the silent house. Dee jumps, unaware of their presence, and Dennis elbows him in the ribs. 

“Jesus Christ,” She says, clutching at her chest. “You scared the crap out of me.”

“Sorry.” 

“It's fine,” She says. She looks at the two of them, glued together at the hip, eyes wide as saucers. “You guys look high as shit.” 

“Yeah, you missed a pretty awesome party,” Dennis says, even though Dee wasn't invited. Dennis was only invited because he’d ran into Tim Murphy in Walmart, Mac in tow as usual. He’d even looked pretty excited to see them. Asshole. 

“Can't have been that awesome,” Dee snorts. “It's only 11:30.” 

Dennis doesn’t have a comeback for that. The heat of Mac’s forearm pressed to his threatening to burn a hole through his skin, and he feels jittery. It’s only 11:30, but Dennis feels like he’s been up for days. 

“Neighbors called the police,” Mac lies easily next to him. 

Dennis raises his eyebrows, shocked and proud that Mac came up with a lie so fast without prompt, like they’re sharing brainwaves as well as beds, like they’re connected spiritually as well as physically. They know each other so well.

“Sounds pretty badass,” She smirks, knowing she’ll get a reaction from Mac. Almost instantly, his eyes light up, and he starts preening a little. 

“It totally was,” He says, grinning smugly. Dennis rolls his eyes, fond, but stops when he glances at Dee. 

She’s checking Mac out, ever so slightly flicking her eyes up and down his body. Dennis scowls. He’s seen her doing it before, and usually thinks it’s hilarious, that she’d even look twice at Mac when he’s never expressed anything more than mild tolerance towards her, but it’s different tonight. She’s blossomed in her first year of college, or at least just lost the back brace. He’s seen the way Charlie looks at her now. 

He feels threatened by her.

He places a possessive hand on Mac’s lower back, pulling him impossibly closer, flush against his side. Dee doesn't seem to notice. 

“We’re going to bed,” He says abruptly, turning Mac away from her. She looks disinterested.

“Night, boners,” She says, turning to watch TV again. 

The garish sound of  _ The Simpsons _ fades as Mac and Dennis disappear down the hallway, Dennis’ hand still on the small of Mac’s back. He lowers it briefly, grabbing his ass, and Mac twists and laughs into his shoulder. 

They’re half-wrestling, hands are all over each other, clumsy and uncoordinated as they stumble up the stairs, and Dennis feels so blind with raw  _ want _ that he almost kisses Mac right there in the hallway, right outside his parents’ ajar bedroom door. 

He holds out though, and manages to kick open the door to his own room, finally, releasing Mac from his grip. 

He busies himself with locking the door while Mac whips out the little baggie, grabbing one of Dennis’ hand-mirrors from the top of his chest of drawers. There’s a lipstick stain on the one he chooses, and Dennis’ blood pressure spikes, terrified of being confronted, but Mac barely bats an eye.

It’s nights like these that make Dennis wonder why he ever wastes his time with anyone else.

He snorts his own line quickly, feeling the headrush set in almost immediately. He knows it's probably mostly adrenaline coursing through his veins when hands the mirror over to Mac, letting his fingers linger a little longer than necessary, but that doesn’t mean it doesn’t feel fucking good. 

Mac grins at him, something like pride on his face when he bows over the mirror. 

Dennis waits a second, bites his lip. 

“Want to fuck me?” He asks, the words just falling out of his mouth, and Mac chokes, white powder spraying out across the mirror. 

They've never done this before.  _ He's  _ never done this before. 

He can’t count the amount of times they’ve gotten high, or drunk, jacked each other off and made out a little, but they’ve never gone past  _ mouth stuff, _ as Mac insists on calling it. 

But he decided a few weeks ago that was he ready, that he just needed to wait for the right time and the right boost of confidence. When Mac had mentioned he could get his hands on his Dad’s secret stash for the party, he knew it'd be today. 

“You serious?” Mac says. He licks a finger, runs it over the mirror, rubs his gums. Dennis watches, engrossed. 

“Yeah,” He breathes. 

For a moment, Mac just stares at him, eyes sparkling. 

“That’s - that’s a sin, dude,” He says, but he’s smiling. “Like, that’s a big one.”

“Yeah.”

“I don’t know if we should.”

“It’s up to you, man.”

Dennis means it. He’s horny as shit, but he’ll just as happily let Mac suck him off (because that’s  _ not _ a sin, apparently) if that’s all he wants to do. 

He looks away from the hungry, torn look on Mac’s face and hops up onto his bed, lounging back on propped up elbows, legs slightly parted. He knows his hard-on is obvious in his pants, because Mac won’t stop staring at it. Dennis smirks. Mac swallows.

“I mean - are you sure?” He asks. 

“One hundred percent.”

“But, like - I don’t want to be gross, but--”

“Mac,” Dennis says, silencing him. His mind flashes back to that morning, spending too long in the bathroom while Dee banged on the door, plastic tube he’d stolen from CVS up his ass, just in case. “I’m sure.” 

Mac rubs his nose a few times, hesitant. 

“I guess - I don’t think He’d mind,” He says slowly. He kneels on the end of the bed, between Dennis’ parted feet. “Just this once.”

Dennis almost laughs. Just this once? 

Mac’d said the same thing the first time he’d closed his eyes and kissed Dennis for the first time, and then again the first time he knelt down and sucked him off.

Just once is never going to be enough. They're obsessed with each other. Dennis has never felt anything like it before. 

“Sure, Mac,” He says, and Mac smiles. “Just this once.”

\---

It’s been at least twenty minutes since their momentous decision to take things to the next level. Most of it’s been spent making out, grabbing at each other’s dicks uselessly while panting into each other’s mouths, but they’ve also managed to strip each other down to nothing. It’s the first time in a while that they’ve been properly exposed to each other like this, and Mac keeps whining against Dennis’ neck, soft and breathy. 

So it comes as a surprise when he’s the one who pulls away first, staring down at Dennis with wide eyes. 

“So, like, you’re going to be the bottom? Or-”

“I think we already know the answer to that,” Dennis says. Mac nods. 

And then it all feels very final, very real. This isn’t a game anymore, it isn’t a fantasy. He’s not just getting jerked off in the back of his dad’s mercedes whilst Mac huffs on his neck, or sucking Mac’s dick in the bathroom of his frat house so his roommate won’t hear. 

Mac is hovering over him, naked and shivering, and Dennis has never felt so vulnerable yet so  _ wanted _ in his life. 

Dennis is going to have his best friends’ dick in his ass in the next five minutes. 

Within the hour, he’ll have the memory of fucking Mac - of letting Mac fuck _him_ \- stored in the back of his head for the rest of his life. 

He wants it all, but  _ god _ , is he nervous. 

“Do you want me to…?” Mac trails off, looking over at the lube on Dennis’ nightstand nervously. Everything feels too vivid. Dennis shudders. 

“Yes,” He breathes. 

He closes his eyes when Mac shifts away from him briefly, mattress dipping with his movements. He feels an inexplicable urge to nuzzle Mac’s forearm he balances himself out beside his head, and he hates it. 

Mac’s silent, save a few shaky breaths, when he uncaps the bottle, the soft snick echoing out into the room like a whisper. Dennis peers at him through half-closed eyes, heart pounding, while Mac slicks up his fingers. They glint in the light a little, and Dennis has to shut his eyes again.

“You okay?” Mac asks. 

“Mhmm.”

“Okay, I’m going to - I’m going to stick one in, now.”

_ Stick one in _ . How crude. Dennis would laugh if he wasn’t so rigid with nerves. 

Mac nudges at Dennis’ thighs hesitantly, already parted but not enough, and Dennis complies, pulls his legs up into against his chest, clutching at his knees. He can feel himself blushing furiously already. 

They both gasp when Mac slips a finger inside of him. He pushes it all the way in, slowly, wiggles around a little, and pulls it almost all the way out again.

It doesn’t exactly feel  _ good _ , but it doesn’t feel bad, either. 

Dennis just kind of lies there as Mac fingers him, sliding in and out without much finesse or tactic. He knows he’s too tensed up to let himself enjoy it, but he doesn’t know how to relax. He’s never felt so on fire before. 

“Mac, I-” He chokes out. Mac looks alarmed, but Dennis grabs his shoulder. “Don’t stop. Just, like, try and find the spot?”

“The spot?” Mac looks genuinely confused. 

“The G-Spot.”

Mac stops and gapes at him. 

“You have a G-Spot in your ass?” He whispers, scandalised. 

“All guys do, idiot,” Dennis says irritably. 

“I’m pretty sure I don’t!”

“I mean, you definitely do, but we’ll deal with that another day,” He snaps, wriggling his hips. Mac starts moving again, crooking his finger a little inside him, but he doesn’t shut up. 

“This is all news to me,” He says, eyebrows furrowed in concentration. 

“Why did you think I’d let you fuck me if I was going to get anything out of it?” 

“I don’t know, because it’s just what people do?”

“Shut the fuck up and--” He stops, sudden, eyes wide. “Oh,  _ shit _ .”

Mac gapes at him. 

“Is that it?” He says, voice full of awe. He rubs the tip of his finger over the same spot again, and again, and Dennis’ breath hitches. He barely manages a nod, but Mac takes this as his cue to start fingering him in earnest.

He’s muttering compliments, showering him with adoration and praise as he inserts another finger, and then another, stretching Dennis out while he whines and writhes underneath him. Dennis has never felt such intense pleasure before, never felt all of his nerve endings give off sparks like this, and he’s white-knuckle clutching the sheets to stop himself from clawing at the smooth, tanned skin of Mac’s back. 

“Mac,” He pants. Mac stops, ever loyal. “Now.”

“Now?” He says, yanking his fingers out of Dennis so fast it’s almost painful. Dennis winces, but nods. 

Mac looks at him for a moment, hesitant, before letting out a shaky laugh, 

“This is really happening, huh?” He says, sitting back on his heels. His pupils are huge, lips shiny and parted, and Dennis doesn’t think he’s ever looked so beautiful. 

“Yeah,” He says quietly, smiling. Mac grins and kisses him. 

“So you wanna stay on your back like this? Or, like, have me behind, or-?” Mac asks, climbing up off the bed to grab his pants off the floor. He digs around in his pocket, unveiling a beat up old wallet that Dennis is pretty sure he bought him for his 16th birthday. 

“I’ll stay like this,” Dennis decides. “If you don’t mind.”

“Why would I mind?” Mac asks, serious, brow furrowed. He pulls a condom out from the worn leather and strides back over to the bed, situating himself between Dennis’ thighs once again. 

“I don’t know, man,” He says, absent mindedly stroking his dick. Mac licks his lips. “In case you didn’t want to see my face, or whatever.”

Mac raises his eyebrows, incredulous.

“Dennis, of course I want to see your face.”

Dennis feels a flush of happiness, despite it all, like a blushing virgin instead of a 19 year old who’s just had his best friend’s fingers up his ass. 

(It still gets to him, sometimes, when he lets himself think about the fact Mac must  _ like _ him, on some level.)

He watches as Mac rips open the packet with fumbling hands, laughing nervously as he goes. He rolls it down his stiff dick, before slicking himself up with lube. For good measure, he pushes some more inside Dennis with his fingers, eliciting a moan from him. 

“Fuck, okay,” Mac says. He crawls up the bed and looms over Dennis, their hips flush, hands planted on either side of his head. “Let's do this.”

Dennis smiles up at him, nervous, and Mac returns it. He leans down to press a long, slow kiss to his mouth, grinding his crotch against Dennis’ a little, and then pulls back. 

The two hands on either side of his head become one as Mac reaches down to guide himself. 

When he pushes inside, head dropped between his shoulders, arms shaking with the effort to hold himself up, Dennis is on fire. 

He doesn’t know how long it takes, whether it’s seconds or minutes, but eventually, his hips meet the backs of Dennis’ thighs, Mac’s head snaps up, and their eyes lock in the darkened room.  

He feels more exposed, more raw than he’s ever felt in his life, and yet Mac’s looking at him like he’s just seeing the moon for the first time. 

“Shit,” He chokes out, garbled. He stays unbelievably still. “I’m -  _ fuck  _ \- I’m not going to last long.”

Dennis doesn’t give a shit. He grabs the back of his neck and pulls him into a searing kiss. It’s overwhelming, how much he needs Mac, how close he needs them to be. He blames the drugs, but he knows the feeling will still be there in the morning, will still be there next week. 

It’s intense, and it’s probably love, but when Mac starts thrusting shallowly, he loses any and all grip on his thoughts. 

He moves with Mac, trying to meet him at every push, thighs shaking uncontrollably. He can hear how loud he’s breathing in the room, whining with every thrust. Mac keeps groaning, which is worse, too loud in the silence of the house, and Dennis would scold him if he wasn’t trying to keep as quiet as possible himself. 

It doesn’t exactly  _ hurt _ ? It feels bizarre, to know someone is inside of him for the first time, but he’s had his own fingers inside himself enough to know what to expect, on some level. He suspects this might not have gone so well if the two of them were sober, but that’s something he doesn’t need to worry about.

His dick is trapped between their stomachs, the friction all too much and not nearly enough at the same time, but when he goes to grab at it, Mac’s hand beats him there. He starts jerking it in time with his thrusts, and Dennis has to bite the inside of his cheeks to hold himself back. 

“That okay?” Mac asks, a genuine question, brows furrowed. 

“ _ Yes _ ,” He bites out. Mac nods, breathless, and starts moving faster.

“You like that?” He says, more determined, dirtier. 

“So good.”

“Yeah? You like it when I do that?” 

“ _ Fuck. _ ”

“You look really beautiful tonight, Dennis,” Mac blurts, feverish, like he can’t stop himself. “Really, really good.”

_ It’s the coke _ , Dennis thinks,  _ it has to be _ . It’s is all too much. Mac is too good to him. No one’s ever called him beautiful before. 

“Mac,” Is all he manages to say, because it’s the only thing running through his brain. He's blushing furiously. He groans and throws an arm up to cover his face, but Mac stops moving, taking his hand off Dennis’ dick to pull it away again. 

“Don’t do that,” He says gently. “I want to see you.”

Dennis could cry.

He kisses Mac instead of responding, locking his legs behind his thighs, pulling him closer. He shifts a little, twisting in Mac’s grip, and then the angle is different, and he’s falling to pieces. A breathless whine escapes his lips before he can stop himself, and Mac gapes at him in awe.

“Is that it?” He says.

“Yeah _ , fuck _ yeah.”

If he thought it felt good before, it’s nothing to what he’s feeling now. His whole body is shaking, electricity coursing through his veins with every movement, and he starts gripping at Mac’s back before he can stop himself, nails digging into pale skin. 

“Don’t stop,” He gasps. “Please, Mac.”

“Dennis.”

“Fuck. Mac, you’re - I can’t--”

“ _ Dennis _ .”

With Dennis’ lips pressed to the damp skin of his neck, still muttering encouragement and obscenities against him, Mac’s hips start stuttering, losing rhythm as he comes undone. He keeps choking out Dennis’ name, fractured and breathless, and then it’s over. 

Mac wasn't lying when he said he wasn't going to last long, and Dennis doesn't even care. 

“Fuck,” He groans, collapsing on top of him. He buries his face in Dennis’ neck for a long moment, nuzzling absent-mindedly into him, whispering nonsense into his hair.  

Dennis reaches up and latches his fingers into Mac’s hair, pulling at the damp locks, bonelessly trying to pull him in for a kiss. He’s painfully hard, still rutting against Mac’s hipbone, but all he wants is Mac’s lips on his.

Mac, however, misconstrues the act. 

“Oh, shit, of course,” He mutters, oblivious to the confusion on Dennis’ face. “Sorry, Den.”

Dennis frowns as Mac pulls away from him. He’s hit by the sudden sensation of loss as Mac’s body leaves his own, cold blast of air stinging his chest, until Mac shuffles backwards on his heels. He grins hastily at the boy below, and then bows to take Dennis’ dick in his mouth. 

The surprise alone is enough to make his breath catch, but when Mac slips two fingers back inside him, stroking over his prostate as best he can, Dennis’ eyes roll into the back of his head. 

Mac blows him messily, like he always does, lacking the technique and finesse that most girls he’s slept with seem to possess, but Dennis fucking  _ loves  _ it. He loves how lost Mac gets in it every time, humming and swallowing around his dick almost frantically, desperate to make him feel good. 

“That’s so good, babe,” He babbles, feeling it spill out of him uncontrollably. Mac preens under the praise, under the pet name, trying harder. “You’re so good at this.”

He doesn’t know how long he’s rambling for, voice sounding too loud and garbled to his own ears, but then there's the familiar tug behind his navel, the white light building behind his eyes before he can suppress it. 

“Mac,” He gasps, blind, grasping at the hairs at the base of his neck, digging his heels into the mattress. “Mac, I'm gonna-”

Mac doesn't pull off. He holds Dennis down with his free hand and sucks harder. 

Yeah. Dennis is definitely in love. 


End file.
